High speed time-interleaved ADC gain offset and skew mitigation

摘要

Methods and apparatuses are described for timing skew mitigation in time-interleaved ADCs (TI-ADCs) that may be performed for any receive signal without any special signals during blind initialization, which may be followed by background calibration. The same gain/skew calibration metrics may be applied to baud sampled and oversampled systems, including wideband receivers and regardless of any modulation, by applying a timing or frequency offset to non-stationary sampled signals during initial training. Skew mitigation is low latency, low power, low area, noise tolerant and scalable. Digital estimation may be implemented with accumulators and multipliers while analog calibration may be implemented with adjustable delays. DC and gain offsets may be calibrated before skew calibration. The slope of the correlation function between adjacent samples may be used to move a timing skew estimate stochastically at a low adaptive rate until the skew algorithm converges.

主权项

1. A device, comprising:
a receiver that receives a transmitted signal at a transmitted symbol frequency, the receiver having a receiver clock frequency, the receiver comprising:
a first sample and hold (SH) that provides samples of a sampled signal to a first set of time-interleaved analog to digital converters (TI-ADCs);a second SH that provides samples of the sampled signal to a second set of TI-ADCs;a frequency offset component that applies a frequency offset that deliberately offsets the transmitted symbol frequency and the receiver clock frequency to make the sampled signal stationary;a gain calibration component that calibrates gain offset between the first and second SHs using samples taken by the first and second SH during the application of the frequency offset; anda skew calibration component that calibrates skew between the first and second SHs using samples taken by the first and second SH during the application of the frequency offset.